A potent antimalarial activity of Hydrangea macrophylla var. Otaksa leaf extract against Plasmodium yoelii 17XL in mice

Medicinal plants as a fight against murine blood-stage malaria

OBJECTIVE

Malaria is an infectious parasitic disease affecting most of countries worldwide. Due to antimalarial drug resistance, researchers are seeking to find another safe efficient source for treatment of malaria. Since many years ago, medicinal plants were widely used for the treatment of several diseases. In general, most application is done first on experimental animals then human. In this article, medicinal plants as antimalarial agents in experimental animals were reviewed from January 2000 until November 2020.

MATERIALS AND METHODS

In this systematic review published articles were reviewed using the electronic databases NCBI, ISI Web of knowledge, ScienceDirect and Saudi digital library to check articles and theses for M.Sc/Ph.D. The name of the medicinal plant with its taxon ID and family, the used Plasmodium species, plant part used and its extract type and the country of harvest were described.

RESULTS AND CONCLUSION

The reviewed plants belonged to 83 families. Medicinal plants of families Asteraceae, Meliaceae Fabaceae and Lamiaceae are the most abundant for use in laboratory animal antimalarial studies. According to region, published articles from 33 different countries were reviewed. Most of malaria published articles are from Africa especially Nigeria and Ethiopia. Leaves were the most common plant part used for the experimental malaria research. In many regions, research using medicinal plants to eliminate parasites and as a defensive tool is popular.

Evaluation of in vitro antimalarial activity of different extracts of Artemisia aucheri Boiss. and A. armeniaca Lam. and fractions of the most potent extracts

Ten extracts with different polarity from two Iranian Artemisia species, A. armeniaca Lam. and A. aucheri Boiss, were screened for their antimalarial properties by in vitro   β-hematin formation assay. Dichloromethane (DCM) extracts of both plants showed significant antimalarial activities with IC₅₀ values of 1.36 ± 0.01 and 1.83 ± 0.03 mg/mL and IC₉₀ values of 2.12 ± 0.04 and 2.62 ± 0.09 mg/mL for A. armeniaca and A. aucheri, respectively. Bioactivity-guided fractionation of DCM extracts of both plants by vacuum liquid chromatography (VLC) over silica gel with solvent mixtures of increasing polarities afforded seven fractions. Two fractions from DCM extract of A. armeniaca and four fractions from DCM extract of A. aucheri showed potent antimalarial activity with reducing IC₅₀ and IC₉₀ values compared to extracts. The most potent fraction belonged to DCM extract of A. armeniaca with IC₅₀ and IC₉₀ values of 0.47 ± 0.006 and 0.71 ± 0.006 mg/mL, respectively.

The course of a primary infection of Plasmodium yoelii 17XL in both 129S1 and IFN-γ receptor-deficient mice

In the present study, we found that 129S1 mice are resistant to the infection with Plasmodium yoelii 17XL, which is highly virulent and causes lethal infection in various strains of mice. In contrast, IFN-γ receptor-deficient (IFN-γR(-/-)) mice on the 129S1 background were much more susceptible than 129S1 mice with intraperitoneal infection with 1 × 10(5) parasitized erythrocytes. The mortality in 129S1 and IFN-γR(-/-) mice was 11.6 and 79.4 %, respectively. Following inoculation of the parasites, both 129S1 and IFN-γR(-/-) mice showed a progressive increase in parasitemia. Growth rate of malaria parasites at the early stages of infection in the IFN-γR(-/-) mice was faster than that in 129S1 mice, and this difference in growth rate might cause the earlier death of IFN-γR(-/-) host from day 8 of infection than that of 129S1. In surviving mice of both strains, however, malaria parasites in their bloodstream began to decrease in number right after a peak of parasitemia and were not detectable by a microscopic examination during the observation period. Next, we investigated the cytokine and antibody production in 129S1 and IFN-γR(-/-) mice during infection. An analysis of cytokines showed that serum IFN-γ and IL-4 levels elevated significantly from day 1 and day 4 of infection, respectively, in both 129S1 and IFN-γR(-/-) mice when compared with the levels from the uninfected controls. Following the infection, significantly higher levels of malaria-specific IgG1 and IgG2a antibodies in the infected 129S1 mice were detected from day 15, and these elevations were coincident with the decrease of parasitemia. On the other hand, the levels of malaria-specific antibodies in IFN-γR(-/-) mice had a tendency to elevate on day 21 but did not reach statistical significance. The present data indicate that IFN-γR plays an essential role in mediating the early immune mechanisms induced by the infection of erythrocytic stages of P. yoelii 17XL parasite, leading to host survival.

Pyrimidine as constituent of natural biologically active compounds

This review describes the various manifestations of the pyrimidine system (alkylated, glycosylated, benzo-annelated.). These comprise pyrimidine nucleosides as well as alkaloids and antibiotics--some of them have been discovered and isolated from natural sources already long time ago, others have been reported very recently. A short overview on pyrimidine syntheses (prebiotic synthesis, biosynthesis, and metabolism) is given. The biological activities of most of the pyrimidine analogs are briefly described, and, in some cases, syntheses are formulated.

Cytokine and antibody production during the course of resolution in Plasmodium yoelii 17XL-infected BALB/c mice treated with febrifugine and isofebrifugine mixture from leaves of Hydrangea macrophylla var. Otaksa

Cytokine and antibody production was investigated during the course of resolution of primary infection in Plasmodium yoelii 17XL-infected BALB/c mice treated with a mixture of febrifugine and isofebrifugine. The infected mice in an untreated control group showed a progressively increasing parasitemia, leading to mouse death. In contrast, infected mice given the mixture orally showed low parasitemia levels during administration. Following a transient increase in parasitemia in the bloodstream of the treated mice, no parasites could be detected by microscopic examination. Analysis of cytokines in plasma showed that the plasma IFN-gamma levels elevated significantly within the first week of infection in both groups. Furthermore, on day 20 the plasma IFN-gamma and IL-4 levels elevated significantly in the treated mice and the production of both cytokines was sustained until at least day 40. The production of both cytokines in the treated mice was coincident with a decrease in parasitemia. The production of parasite-specific antibodies in the course of P. yoelii 17XL infection was also monitored. In the drug-treated mice, the titers of parasite-specific IgG1, IgG2a, IgG2b and IgG3 elevated significantly from day 20; and the production of parasite-specific antibodies was coincident with a decrease in parasite numbers in the bloodstream.

Combination effects of chloroquine with the febrifugine and isofebrifugine mixture against a blood-induced infection with chloroquine-resistant Plasmodium berghei NK65 in ICR mice

The combination effects of chloroquine with a mixture of febrifugine and isofebrifugine were evaluated against a blood-induced infection with chloroquine-resistant P. berghei NK65 in ICR mice. Mice in the untreated control showed a progressively increasing parasitemia leading to mouse death. A two-day dosage of 20 mg base/kg of chloroquine alone showed little effect against P. berghei NK65 infection, and all mice died from day 13 to 14 with an increasing parasitemia. A four-day dosage of 1 mg/kg of the febrifugine and isofebrifugine mixture alone showed a little antimalarial activity, but all mice died from day 19 to 27 with an increasing parasitemia. On the other hand, mice treated with chloroquine plus alkaloids survived during the experiment. All mice treated with chloroquine alone or the alkaloid mixture alone showed low parasitemia levels during a drug administration and following a few days, but then malaria parasites increased in the bloodstream of the treated mice until death. On the other hand, malaria parasites in the mice given chloroquine plus alkaloids decreased on day 6 and then were not detected by a microscopic examination during observation period.

Different responses of three rodent Plasmodia species, Plasmodium yoelii 17XL, P. berghei NK65 and P. chabaudi AS on treatment with febrifugine and isofebrifugine mixture from Hydrangea macrophylla var. Otaksa leaf in ICR mice

The antimalarial activity of Hydrangea macrophylla var. Otaksa alkaloids was evaluated against Plasmodium yoelii 17XL, P. berghei NK65 and P. chabaudi AS in ICR mice. For trials in P. yoelii 17XL or P. chabaudi AS infections, mice were infected intraperitoneally with 10(5), 10(6) and 10(7) parasitized erythrocytes, respectively, and in P. berghei NK65 infections, mice were infected intraperitoneally with 10(3), 10(4) and 10(5) parasitized erythrocytes, respectively. Three days after injection, mice were orally given febrifugine and isofebrifugine mixture at 1 mg/kg in the treated group and 0.5% cremophor EL solution in the untreated, infected one, respectively, twice a day for 5 consecutive days. In P. yoelii 17XL infections, mice in all the non-treated controls died from 5 to 9 dpi with a gradual body weight loss and increasing parasitemias. In the treated groups, the mouse body weight gradually decreased after the end of administration but turned to increase in several days, and except one mouse in the group given 10(6) parasitized erythrocytes, other mice survived during the experiment. Mice given orally the mixture showed low parasitemia levels during administration. Following a transient recrudescence of malaria parasites in the bloodstream of treated mice, no parasites could be detected by a microscopic examination. In P. berghei NK65 infections, mice in all the non-treated controls died from 7 to 12 dpi with a gradual body weight loss and increasing parasitemias. In the treated groups, the body weight gradually decreased from 11 dpi and all mice died from 12 to 30 dpi. During a mixture administration all mice showed slight suppression of multiplication of malaria parasites. After the end of administration, however, malaria parasites increased in the bloodstream of the treated mice and all mice died. In P. chabaudi AS infections, there were two different patterns in the course of infection; lethal infection or recovery in both the non-treated control and treated groups. In the non-treated and treated groups, mice showed a gradual body weight loss. But the body weights of survivals in both groups turned to increase in several days. Mice in control and treated groups showed as the same profile in the changes of parasitemia. In the non-treated controls, after a transient peak parasitemia malaria parasites in the bloodstream of survivals could not be detected by a microscopic examination. During a mixture administration, all mice showed suppression of multiplication of malaria parasites. After the end of medication, some mice died with increasing parasitemia. After a transient recrudescence, however, malaria parasites in the bloodstream of survivals could not be detected by a microscopic examination.

Comparison of antimalarial activity of the alkaloidal fraction of Hydrangea macrophylla var. Otaksa leaves with the hot-water extract in ICR mice infected with Plasmodium yoelii 17 XL

The antimalarial activity of the fractions isolated from the leaves of Hydrangea macrophylla Seringe var. Otaksa Makino was evaluated against Plasmodium yoelii 17 XL in mice. Four different fractions were prepared in the usual manner to obtain an alkaloid fraction. All mice treated with the fraction containing febrifugine and isofebrifugine mixture at 1 mg/kg twice a day for 5 consecutive days survived during the experiment, and the change of mean parasitemia level showed almost the same pattern as that from mice treated with the hot-water extract of the same plant leaves. Activity of this fraction, however, was markedly reduced compared with the hot-water extract. Furthermore, no antimalarial activity was shown in the hotwater extract from H. macrophylla var. Otaksa roots or Dichroa febrifuga Lour. leaves.